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1 // Copyright 2014 the V8 project authors. All rights reserved. | 1 // Copyright 2014 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef V8_LOOKUP_H_ | 5 #ifndef V8_LOOKUP_H_ |
6 #define V8_LOOKUP_H_ | 6 #define V8_LOOKUP_H_ |
7 | 7 |
8 #include "src/factory.h" | 8 #include "src/factory.h" |
9 #include "src/isolate.h" | 9 #include "src/isolate.h" |
10 #include "src/objects.h" | 10 #include "src/objects.h" |
11 | 11 |
12 namespace v8 { | 12 namespace v8 { |
13 namespace internal { | 13 namespace internal { |
14 | 14 |
15 // Cache for mapping (map, property name) into descriptor index. | |
16 // The cache contains both positive and negative results. | |
17 // Descriptor index equals kNotFound means the property is absent. | |
18 // Cleared at startup and prior to any gc. | |
19 class DescriptorLookupCache { | |
20 public: | |
21 // Lookup descriptor index for (map, name). | |
22 // If absent, kAbsent is returned. | |
23 inline int Lookup(Map* source, Name* name); | |
24 | |
25 // Update an element in the cache. | |
26 inline void Update(Map* source, Name* name, int result); | |
27 | |
28 // Clear the cache. | |
29 void Clear(); | |
30 | |
31 static const int kAbsent = -2; | |
32 | |
33 private: | |
34 DescriptorLookupCache() { | |
35 for (int i = 0; i < kLength; ++i) { | |
36 keys_[i].source = NULL; | |
37 keys_[i].name = NULL; | |
38 results_[i] = kAbsent; | |
39 } | |
40 } | |
41 | |
42 static inline int Hash(Object* source, Name* name); | |
43 | |
44 static const int kLength = 64; | |
45 struct Key { | |
46 Map* source; | |
47 Name* name; | |
48 }; | |
49 | |
50 Key keys_[kLength]; | |
51 int results_[kLength]; | |
52 | |
53 friend class Isolate; | |
54 DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache); | |
55 }; | |
56 | |
57 // Cache for mapping (map, property name) into field offset. | |
58 // Cleared at startup and prior to mark sweep collection. | |
59 class KeyedLookupCache { | |
60 public: | |
61 // Lookup field offset for (map, name). If absent, -1 is returned. | |
62 int Lookup(Handle<Map> map, Handle<Name> name); | |
63 | |
64 // Update an element in the cache. | |
65 void Update(Handle<Map> map, Handle<Name> name, int field_offset); | |
66 | |
67 // Clear the cache. | |
68 void Clear(); | |
69 | |
70 static const int kLength = 256; | |
71 static const int kCapacityMask = kLength - 1; | |
72 static const int kMapHashShift = 5; | |
73 static const int kHashMask = -4; // Zero the last two bits. | |
74 static const int kEntriesPerBucket = 4; | |
75 static const int kEntryLength = 2; | |
76 static const int kMapIndex = 0; | |
77 static const int kKeyIndex = 1; | |
78 static const int kNotFound = -1; | |
79 | |
80 // kEntriesPerBucket should be a power of 2. | |
81 STATIC_ASSERT((kEntriesPerBucket & (kEntriesPerBucket - 1)) == 0); | |
82 STATIC_ASSERT(kEntriesPerBucket == -kHashMask); | |
83 | |
84 private: | |
85 KeyedLookupCache() { | |
86 for (int i = 0; i < kLength; ++i) { | |
87 keys_[i].map = NULL; | |
88 keys_[i].name = NULL; | |
89 field_offsets_[i] = kNotFound; | |
90 } | |
91 } | |
92 | |
93 static inline int Hash(Handle<Map> map, Handle<Name> name); | |
94 | |
95 // Get the address of the keys and field_offsets arrays. Used in | |
96 // generated code to perform cache lookups. | |
97 Address keys_address() { return reinterpret_cast<Address>(&keys_); } | |
98 | |
99 Address field_offsets_address() { | |
100 return reinterpret_cast<Address>(&field_offsets_); | |
101 } | |
102 | |
103 struct Key { | |
104 Map* map; | |
105 Name* name; | |
106 }; | |
107 | |
108 Key keys_[kLength]; | |
109 int field_offsets_[kLength]; | |
110 | |
111 friend class ExternalReference; | |
112 friend class Isolate; | |
113 DISALLOW_COPY_AND_ASSIGN(KeyedLookupCache); | |
114 }; | |
115 | |
116 class LookupIterator final BASE_EMBEDDED { | 15 class LookupIterator final BASE_EMBEDDED { |
117 public: | 16 public: |
118 enum Configuration { | 17 enum Configuration { |
119 // Configuration bits. | 18 // Configuration bits. |
120 kInterceptor = 1 << 0, | 19 kInterceptor = 1 << 0, |
121 kPrototypeChain = 1 << 1, | 20 kPrototypeChain = 1 << 1, |
122 | 21 |
123 // Convience combinations of bits. | 22 // Convience combinations of bits. |
124 OWN_SKIP_INTERCEPTOR = 0, | 23 OWN_SKIP_INTERCEPTOR = 0, |
125 OWN = kInterceptor, | 24 OWN = kInterceptor, |
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454 const Handle<JSReceiver> initial_holder_; | 353 const Handle<JSReceiver> initial_holder_; |
455 const uint32_t index_; | 354 const uint32_t index_; |
456 uint32_t number_; | 355 uint32_t number_; |
457 }; | 356 }; |
458 | 357 |
459 | 358 |
460 } // namespace internal | 359 } // namespace internal |
461 } // namespace v8 | 360 } // namespace v8 |
462 | 361 |
463 #endif // V8_LOOKUP_H_ | 362 #endif // V8_LOOKUP_H_ |
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